Various recreational watercraft have been proposed for allowing users to mechanically propel themselves in bodies of water. Such devices are typically used for recreation, but can also provide a pleasurable method of exercising.
One such recreational water device is disclosed in U.S. Pat. No. 1,071,113 to Teters, titled "Swimming Appliance." The user lies generally prone in a bow member which is suspended from a substantially planar frame. The user pedals and propels the appliance by means of a rear propeller mounted on a shaft lying within the plane of the frame. Thus, the thrust of the propeller includes a vector component which is directed at an angle upward which, when translated to the intended horizontal motion of the water device, results in an inefficient use of thrust. When in use, both the stern and bow of the swimming appliance are submerged in the water with the stern significantly submerged beneath the water, substantially below the bow, thereby positioning the user in an unnatural position. That is, the user is awkwardly positioned with its entire body submerged beneath the surface of the water and the user must hold its head above the water surface which, seemingly, strains the user's neck muscles. Further, the device to Teters includes a centrally positioned rear propeller which provides a less stable buoyant support and less efficient use of the thrust of the propeller than a device having two spaced apart propellers with thrust generated in the intended propulsion direction. Moreover, the propeller and associated gearing are exposed creating a potential danger both to the user and other nearby swimmers.
U.S. Pat. No. 5,368,507 to Harris, titled "Paddle Board", relates to a recreational aquatic device having a main body with a fore and aft portion which substantially extend along the same plane. While effective for its intended use, the apparatus includes a gearing mechanism having a plurality of gears for altering the gear ratios to reduce or enhance the pedaling action of the user.
U.S. Pat. No. 1,578,584 to Cromer, titled "Swimming Apparatus", discloses a recreational water device in which the user lies generally prone on an inclined support member. Two paddle wheels mounted on a pair of transverse shafts adjacent to the user's head are driven by a second pair of longitudinally extending shafts driven by a pair of rotatable pedals. The Cromer apparatus also has exposed moving parts.
A pedal-driven swimming support is also disclosed in French Published Pat. Application No. 73 46435. The swimming support is propelled by means of a propeller mounted on the rear of the frame. The pedals drive gear wheels which drive a flexible cable which in turn drives a propeller. As can be seen in FIG. 1, however, the device has a generally planar frame with the rearward end being submerged below the surface of the water. Thus, a component part of the thrust of the propeller is directed downwardly instead of in the horizontal direction in which the swimming support moves.